1. Field of the Invention
The present invention relates to a mobile telecommunication system, and more particularly to a method and system for transmitting packet data.
2. Background of the Related Art
In cellular/PCS/IMIT-2000 mobile telecommunication systems, when a user of a mobile station (MS) wants service accessed through the internet, a point-to-point (PPP) link or a link which enables exchange of internet IP datagrams is established between the mobile station and a packet data serving node (PDSN) through a base transceiver system (BTS) and a base station controller (BSC). An IP address is then allocated by the PDSN or a home agent (HA) to the mobile station through the link. This address allows the mobile station to communicate with an IP host/server on the internet.
In order to authenticate internet network access and handle charging fees of the mobile station, a network access identifier (NAI) of the mobile station is transferred to an authentication, authorization, accounting (AAA) server when a link is established between the MS and PDSN. The AAA server controls the authentication, authorization and accounting of the corresponding terminal based on the NAI of each mobile station requesting internet service.
When the mobile station is connected to the PDSN through a PPP link, the mobile station communicates with the IP host/server freely. When the IP host/server is going to provide the mobile station with IP push service (provided randomly by a service provider at the request of an MS user), the IP push server sends an IP datagram to the IP address of the corresponding mobile station user as a destination address, provided there is an IP address identifying a fixed MS user.
However, a simple IP user (to whom a dynamic address is allotted by a local PDSN) and a mobile IP user (to whom an IP address is allotted dynamically every access to the internet) are unable to receive IP push service since the IP push server does not recognize the IP address allotted when the mobile station establishes a link to the PDSN. This is because the simple IP user and the mobile IP user have no permanently-allotted IP address as a result of the dynamic HA allotment. The method according to a related art is therefore unable to send an IP datagram substantially by having the IP push server identify the IP address of a mobile station user.